This research endeavor involves a multi-faceted approach to the investigation of knee ligamentous injuries from three standpoints: 1. We will be testing in vivo the static and dynamic properties of knee ligaments using impedance testing technique. We will evaluate the impedance curves of individuals who have sustained varying patterns of knee ligamentous injuries using classical follow-up study techniques, incorporating the impedance testing during that follow-up. 2. We will evaluate the biomechanical properties of human ligamentous materials removed from fresh cadaver material. This ligamentous material will be tested to establish the failure loads and modes by subjecting them to strain rates equivalent to those occurring in real injuries. 3. We will be studying the relationship of the function of ski binding equipment to the production of knee ligamentous injuries, along with other injuries produced by failure of the ski-boot-binding systems to function correctly.